Last updated on November 18th, 2025 at 06:25 pm

Possible reasons to switch

• Teriflunomide reduces the relapse rate and acquisition of disability by ~30%.
• It reduces MRI activity by ~70% and slows down brain volume loss.
• It is not immunosuppressive; no increase in serious infections has been observed with teriflunomide.
• Teriflunomide is not associated with a blunted antibody response to vaccines or low lymphocyte counts.
• People who start teriflunomide as a second-line or third-line DMT do better than those using it first-line; the reason for this is unclear.

Reasons for caution

• The European Medicines Agency (EMA) requires blood monitoring to be done every 4 weeks for 6 months and regularly after that when teriflunomide is started.
• People with pre-existing liver disease or those who consume excessive quantities of alcohol may be at increased risk of developing elevated liver enzymes on teriflunomide.
• It is unsuitable for women of childbearing age who are planning to start, or extend, their families. Women on teriflunomide should not breastfeed.
• It takes many months to eliminate teriflunomide from the body on stopping treatment; therefore, contraception must be continued during the drug elimination period.
• Severe hypersensitivity skin reactions have been reported on teriflunomide; please look out for any skin rash.

Interferon and glatiramer acetate

In general, teriflunomide can be started immediately after discontinuation of interferon or glatiramer acetate. It is important that all the recommended baseline screening tests and vaccination reviews are done before starting teriflunomide.

Natalizumab

Owing to the risk of rebound activity on stopping natalizumab, a prolonged wash-out period is not recommended before starting teriflunomide. Most often the reason for switching from natalizumab to teriflunomide, or another DMT, is to reduce the risk of carry-over PML (progressive multifocal leukoencephalopathy) from natalizumab. In our centre, we do an MRI and a lumbar puncture for cerebrospinal fluid analysis to exclude JC virus-DNA on polymerase chain reaction testing. Provided these two tests are clear, we would typically initiate teriflunomide as soon as possible after the last natalizumab infusion. We tend, however, not to use teriflunomide post-natalizumab because the data demonstrating that teriflunomide can prevent rebound activity is not as strong as for fingolimod and anti-CD20 therapies. All the recommended baseline screening tests and vaccination reviews must be done before starting teriflunomide.

S1P modulators (fingolimod, siponimod, ozanimod and ponesimod)

Because fingolimod has quite a long half-life, some neurologists recommend a short washout period, i.e. 4 ̶ 6 weeks; this may be appropriate, depending on the reason for switching. I recommend waiting for the total peripheral lymphocyte counts to go above 800/mm³ to exclude the uncommon occurrence of persistent lymphopaenia following S1P modulator administration. It is important that all the recommended baseline screening tests and vaccination reviews are done before starting teriflunomide. If you are switching because of abnormal liver function tests on a S1P modulator, you would ideally want the liver enzymes to normalise or at least drop to below three times the upper limit of normal before starting teriflunomide.

Fumarates

It is important that all the recommended baseline screening tests and vaccination reviews are done before starting teriflunomide. If lymphopaenia is the main reason for switching from a fumarate, I recommend waiting for the total peripheral lymphocyte counts to go above 800/mm³.

Alemtuzumab

It is important that all the recommended baseline screening tests and vaccination reviews are done before starting teriflunomide. I recommend waiting for the total peripheral lymphocyte counts to go above 800/mm³ before starting teriflunomide.

Anti-CD20 therapies (selective cell depleting DMTs)

It is important that all the recommended baseline screening tests and vaccination reviews are done before starting teriflunomide.

Cladribine (selective cell depleting DMT)

It is important that all the recommended baseline screening tests and vaccination reviews are done before starting teriflunomide. I recommend waiting for the total peripheral lymphocyte counts to exceed 800/mm³.

Mitoxantrone

I recommend waiting for the neutrophil and total peripheral lymphocyte counts to go above 1,000/mm³ and 800/mm³, respectively. All the recommended baseline screening tests and vaccination reviews must be done before starting teriflunomide.

HSCT

I recommend waiting for the neutrophil and total peripheral lymphocyte counts to go above 1,000/mm³ and 800/mm³, respectively. All the recommended baseline screening tests must be done before starting teriflunomide.